the values of the level scales as determined by Mr Simms (which I have no reason to believe to be inaccurate) the spring and autumn observations of 1871 absolutely negative the idea of any effect being produced on the constant of aberration by the amount of refracting medium traversed by the light.—­The great Aurora of 1872 Feb. 4 was well observed.  On this occasion the term Borealis would have been a misnomer, for the phenomenon began in the South and was most conspicuous in the South.  Three times in the evening it exhibited that umbrella-like appearance which has been called (perhaps inaccurately) a corona.  I have very carefully compared its momentary phenomena with the corresponding movements of the magnetometers.  In some of the most critical times, the comparison fails on account of the violent movements and consequent faint traces of the magnetometers.  I have not been able to connect the phases of aurora and those of magnetic disturbance very distinctly.—­The Report contains a detailed account of the heavy preparations for the observation of the Transit of Venus 1874, including the portable buildings for the instruments, the instruments themselves (being a transit-instrument, an altazimuth, and an equatoreal, for each station), and first class and second-class clocks, all sufficient for the equipment of 5 stations, and continues thus:  I was made aware of the assent of the Government to the wish of the Board of Visitors, as expressed at their last meeting, that provision should be made for the application of photography to the observation of the Transit of Venus.  It is unnecessary for me to remark that our hope of success is founded entirely on our confidence in Mr De La Rue.  Under his direction, Mr Dallmeyer has advanced far in the preparation of five photoheliographs....  The subject is recognized by many astronomers as not wholly free from difficulties, but it is generally believed that these difficulties may be overcome, and Mr De La Rue is giving careful attention to the most important of them.—­I take this opportunity of reporting to the Board that the Observatory was honoured by a visit of His Majesty the Emperor of Brazil, who minutely examined every part.”—­After referring to various subjects which in his opinion might be usefully pursued systematically at the Observatory, the Report proceeds thus:  “’The character of the Observatory would be somewhat changed by this innovation, but not, as I imagine, in a direction to which any objection can be made.  It would become, pro tanto, a physical observatory; and possibly in time its operations might be extended still further in a physical direction.’—­The consideration of possible changes in the future of the Observatory leads me to the recollection of actual changes in the past.  In my Annual Reports to the Visitors I have endeavoured to chronicle these; but still there will be many circumstances which at present are known only to myself, but which ought not to be beyond the reach of history.  I have therefore